Endovascular devices and methods

ABSTRACT

Devices and methods for the treatment of chronic total occlusions are provided. One disclosed embodiment comprises a method of facilitating treatment via a vascular wall defining a vascular lumen containing an occlusion therein. The method includes providing an intravascular device having a distal portion with a side port, inserting the device into the vascular lumen, positioning the distal portion in the vascular wall, directing the distal portion within the vascular wall such that the distal portion moves at least partially laterally, and directing the side port towards the vascular lumen.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of application Ser. No. 13/079,179, filed Apr. 4,2011, which is a continuation of application Ser. No. 11/518,428, filedSep. 11, 2006, now U.S. Pat. No. 7,938,819, which claims the benefit ofU.S. Provisional Application No. 60/716,287, filed Sep. 12, 2005, under35 U.S.C. § 119(e). In addition, this application also claims thebenefit of U.S. Provisional Application No. 60/717,726, filed Sep. 15,2005, under 35 U.S.C. § 119(e). In addition, this application alsoclaims the benefit of U.S. Provisional Application No. 60/727,819, filedOct. 18, 2005, under 35 U.S.C. § 119(e). The entire disclosure of eachof the above-referenced applications is incorporated by referenceherein.

FIELD OF THE INVENTION

The inventions described herein relate to devices and associated methodsfor the treatment of chronic total occlusions. More particularly, theinventions described herein relate to devices and methods for crossingchronic total occlusions and subsequently performing balloonangioplasty, stenting, atherectomy, or other endovascular methods foropening occluded blood vessels.

BACKGROUND OF THE INVENTION

Due to age, high cholesterol and other contributing factors, a largepercentage of the population has arterial atherosclerosis that totallyoccludes portions of the patient's vasculature and presents significantrisks to patient health. For example, in the case of a total occlusionof a coronary artery, the result may be painful angina, loss of cardiactissue or patient death. In another example, complete occlusion of thefemoral and/or popliteal arteries in the leg may result in limbthreatening ischemia and limb amputation.

Commonly known endovascular devices and techniques are eitherinefficient (time consuming procedure), have a high risk of perforatinga vessel (poor safety) or fail to cross the occlusion (poor efficacy).Physicians currently have difficulty visualizing the native vessellumen, cannot accurately direct endovascular devices toward visualizedlumen, or fail to advance devices through the lesion. Bypass surgery isoften the preferred treatment for patients with chronic totalocclusions, but less invasive techniques would be preferred.

SUMMARY OF THE INVENTION

To address this and other unmet needs, the present invention provides,in exemplary non-limiting embodiments, devices and methods for thetreatment of chronic total occlusions. The disclosed methods and devicesare particularly beneficial in crossing coronary total occlusions butmay also be useful in other vessels including peripheral arteries andveins. In exemplary embodiments, total occlusions are crossed usingmethods and devices intended to provide a physician the ability to placea device within the subintimal space, delaminate the connective tissuesbetween layers within the lesion or vessel wall, or remove tissues fromthe chronic total occlusion or surrounding vessel.

In an aspect of the disclosure, a subintimal device may be used to guideconventional devices (for example guide wires, stents, lasers,ultrasonic energy, mechanical dissection, or atherectomy) within thevessel lumen. Additionally, a subintimal device may be used todelaminate vessel wall layers and also may be used to remove tissue fromthe occlusive lesion or surrounding vessel wall. In one example, thepositioning of a subintimal device or the establishment of adelamination plane between intima and medial layers is achieved throughthe use of a mechanical device that has the ability to infuse a fluid(for example saline). Fluid infusion may serve to apply a hydraulicpressure to the tissues and aid in layer delamination and may also serveto protect the vessel wall from the tip of the subintimal device andreduce the chance of vessel perforation. The infusion of fluid may becontrolled by pressure or by volume.

Subintimal device placement may be achieved with a subintimal devicedirecting catheter. The catheter may orient a subintimal device so thatit passes along the natural delamination plane between intima and media.The catheter may orient the subintimal device in various geometries withrespect to the vessel. For example, the subintimal device may bedirected substantially parallel with respect to the vessel lumen or in ahelical pattern such that the subintimal device encircles the vessellumen in a coaxial fashion. The subintimal device directing catheter maybe an inflatable balloon catheter having proximal and distal ends withtwo wire lumens. One lumen may accept a conventional guide wire whilethe second lumen may accept the subintimal device. In an alternativeembodiment, the wire directing catheter may be a guide catheter withdistal geometry that steers the subintimal device with the appropriateorientation to enter the subintimal space.

In an additional disclosure, a subintimal device intended tomechanically delaminate tissue layers may use a device that is insertedinto the subintimal space in a first collapsed configuration and isreleased or actuated into a second expanded configuration. The devicemay then be withdrawn or manipulated to propagate the area ofdelamination.

An additional aspect of the disclosure may allow the physician to removetissues from the lesion or vessel wall. In one embodiment, a subintimaldevice is circumferentially collapsed around the total occlusion. Tissueremoval is performed through simple device withdrawal or through aprocedure that first cuts connective tissues (i.e. the intimal layerproximal and distal of the lesion) and then removes the targeted tissue.In another embodiment, a tissue removal device is passed through thelesion within the native vessel lumen. The targeted tissues may bemechanically engaged and removed through device withdrawal.

BRIEF DESCRIPTION OF THE DRAWINGS

It is to be understood that both the foregoing summary and the followingdetailed description are exemplary. Together with the following detaileddescription, the drawings illustrate exemplary embodiments and serve toexplain certain principles. In the drawings,

FIG. 1 shows an illustration of a heart showing a coronary artery thatcontains a chronic total occlusion;

FIG. 2 is a schematic representation of a coronary artery showing theintimal, medial and adventitial layers;

FIG. 3 is a partial sectional view of a subintimal device directingballoon catheter embodiment with fluid infusion through the subintimaldevice lumen within the device directing catheter;

FIG. 4 is a partial sectional view of a subintimal device directingballoon catheter embodiment with fluid infusion through the subintimaldevice;

FIG. 5 is a partial sectional view of an additional subintimal devicedirecting guiding catheter embodiment with fluid infusion through thesubintimal device;

FIGS. 6A and B are partial sectional views of a expandable delaminationcatheter;

FIGS. 7 A-D are partial sectional views of a circumferential subintimaltissue removal device;

FIGS. 8A-C are an example of subintimal device construction;

FIGS. 9A and B are partial sectional views of an intraluminal rotationalengagement tissue removal device;

FIG. 10 is a schematic illustration of an alternative subintimal device;

FIGS. 11A and 11B are schematic illustrations of an alternativesubintimal device with a re-entry port;

FIGS. 12A-12D are schematic illustrations of a re-entry method using aballoon catheter; and

FIGS. 13A and 13B are schematic illustrations of an alternativesubintimal device and associated pumping system.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following detailed description should be read with reference to thedrawings in which similar elements in different drawings are numberedthe same. The drawings, which are not necessarily to scale, depictillustrative embodiments and are not intended to limit the scope of theinvention.

Referring to FIG. 1, a diseased heart 100 includes a chronic totalocclusion 101 of a coronary artery 102. FIG. 2 shows coronary artery 102with intimal layer 200 (for sake of clarity, the multi layer intima isshown as a single homogenous layer). Concentrically outward of theintima is the medial layer 201 (which also is comprised of more than onelayer but is shown as a single layer). The transition between theexternal most portion of the intima and the internal most portion of themedia is referred to as the subintimal space. The outermost layer of theartery is the adventitia 202.

In an aspect of the disclosure, a subintimal device may be used to guideconventional devices (for example guide wires, stents, lasers,ultrasonic energy, mechanical dissection, or atherectomy) within thevessel lumen. Additionally, a subintimal device may be used todelaminate vessel wall layers and also may be used to remove tissue fromthe occlusive lesion or surrounding vessel wall. In one embodiment, FIG.3 shows a subintimal device directing catheter is 300 with its distalballoon 301 that has been advanced over a conventional guide wire 302and inflated proximal to chronic total occlusion 101. For the sake ofclarity, FIG. 4 shows a subintimal device path that is substantiallyparallel to the vessel lumen, but other orientations (i.e. helical) mayalso be considered. Subintimal device lumen 303 is positioned adjacentto the intimal layer 200 and subintimal device 304 has been advanced asto perforate the subintimal layer. A fluid source (i.e. syringe) 305 isin fluid communication with subintimal device lumen 303 through infusionlumen 306. Fluid may flow from the fluid source 305 through thesubintimal device lumen 303 under a controlled pressure or a controlledvolume. The infused fluid may enter the subintimal space 307 directlyfrom the subintimal device lumen 303 or from the volume 308 defined bythe distal end of the balloon 301 and the proximal edge of the lesion101. FIG. 4 shows an alternative fluid infusion path where fluid source305 is in fluid communication with a lumen within the subintimal device304. FIG. 5 shows an alternative subintimal device directing guidecatheter 500 where the distal end 501 has a predefined shape or thedistal end has an actuating element that allows manipulation by thephysician intraoperatively.

Another aspect of the disclosure may place a subintimal device withinthe subintimal space in a first collapsed configuration and releases oractuated the subintimal device to a second expanded configuration. Thedevice may then be withdrawn or manipulated to propagate the subintimaldissection. In one embodiment, FIG. 6A shows a subintimal device withinternal expandable element 600 that contains one or more expandingelements contained in exterior sheath 602. FIG. 6B shows exterior sheathin a retracted position allowing expanding elements 601 to elasticallyexpand. The subintimal device is intended to be delivered through theaforementioned subintimal device delivery catheters.

An additional aspect of the disclosure may allow the physician to removetissues from the lesion or vessel wall. FIG. 7A shows an embodimentwhere subintimal device directing balloon catheter is inflated withincoronary artery 102 just proximal to chronic total occlusion 101.Subintimal device 304 is partially delivered around chronic totalocclusion 102 coaxially outside the intimal layer 200 and coaxiallyinside medial layer 201 in a helical pattern. FIG. 7B shows a subintimaldevice capture catheter 702 positioned across the chronic totalocclusion 101 over conventional guide wire 703 and within subintimaldevice 304. The distal 704 and proximal 705 ends of the subintimaldevice have been captured and rotated as to reduce the subintimal deviceoutside diameter and contain the lesion 101 and intima 200 within thecoils internal diameter. The device may be withdrawn through the use ofa cutting element. For example, FIGS. C and D show the advancement of acutting element 706 in two stages of advancement showing the cutting ofintima 200 proximal of the occlusion 707 and intimal distal of theocclusion 708.

An additional aspect of the subintimal device is the construction of thedevice body. The flexibility and torquability of the device body canaffect the physician's ability to achieve a subintimal path. Thesubintimal device body may be constructed in part or in to total of asingle layer coil with geometric features along the coil length thatallow adjacent coils to engage (for example mechanical engagementsimilar to the teeth of a gear). FIG. 8A shows coil 801 closely woundsuch that the multitude of teeth 802 along the coil edges are in contactsuch that the peaks of one coil falls within the valleys of the adjacentcoil. A conventional coil reacts to an applied torsional load bydiametrically expanding or contracting, thus forcing the wire surfaceswithin a turn of the coil to translate with respect to its neighboringturn. The construction of coil 801 resists the translation of wiresurfaces within the coil thus resisting the diametric expansion orcontraction (coil deformation). An increased resistance to coildeformation increases the torsional resistance of the device body whilethe coiled construction provides axial flexibility. An exemplaryconstruction may include a metallic tube where the coil pattern 801 andteeth 802 are cut from the tube diameter using a laser beam. FIG. 8Bshows subintimal device body 804 that is for example a continuousmetallic tube with distal laser cut coil segment 801 and proximal solidtube 803. Tube materials include but are not limited to stainless steeland nickel titanium. Alternatively, the coil may be wound from acontinuous wire. The wire has a cross section that for example has beenmechanically deformed (stamped) to form the teeth and allow coilengagement. FIG. 8C shows an example of a laser cut tooth pattern fromthe circumference of a tube that has been shown in a flat configurationfor purposes of illustration.

In another embodiment, a tissue removal device may be passed through thelesion within the native vessel lumen. FIG. 9A shows corkscrew device900 with exterior sheath 902 engaging occlusion after delamination ofthe intimal layer 901 has been performed by the aforementioned methodsand devices. FIG. 9B shows removal of the occlusion and a portion of theintimal layer through axial withdrawal of the corkscrew device.

With reference to FIG. 10, an alternative subintimal device 1000 isshown schematically. Subintimal device 1000 is similar to the deviceshown and described with reference to FIGS. 8A-8C, and may include anyof the variants described previously, such as distal atraumatic tipconfigurations, fluidic dissection mechanisms, etc. Subintimal device1000 may be sized and shaped for intravascular navigation and includesan elongate tubular shaft 1004, at least a distal portion of whichincludes a helical interlocking gear 1006 and a helical wire coil 1008disposed thereon. A helically shaped inner mandrel or tube 1010 may bedisposed in the tubular shaft 1004 such that the shaft 1004 rotatesfreely thereon. The shaft 1004 may have a linear or straightconfiguration in a relaxed state and a helical configuration (shown)when the helically shaped inner member 1010 is disposed therein. Thedevice 1000 may be disposed in a constraining sheath (not shown) andnavigated to the intravascular site, such as the site of an occlusion.When the device 1000 is advanced distally out the end of theconstraining sheath or when the sheath is pulled proximally relativethereto, the distal portion of the device 1000 assumes a helical shapeas shown. The shaft 1004 may be rotated relative to the inner member1010 to cause rotation of the helical wire threads 1008, which may beused to engage the vessel wall and advance around an occlusion in asubintimal path as described previously. A bearing (not shown) may bedisposed on the inner member 1010 to engage the proximal or distal endof the shaft 1004 to enable the shaft 1004 and the inner member 1010 tobe advanced in unison.

With reference to FIGS. 11A and 11B, an alternative subintimal device1100 is shown schematically. Subintimal device 1100 may be similar todevice 1000 described previously, with the helical interlocking gear andhelical wire coil eliminated for sake of illustration. Subintimal device1100 includes an elongate tubular shaft 1102 having a lumen extendingtherethrough and a re-entry port 1106 disposed distally in the region ofthe helical shape. In this embodiment, the distal portion of the shaft1102 may have a helical shape in its relaxed state such that there-entry port 1106 is always oriented toward the center of the helix asshown in FIG. 11A. With this arrangement, a re-entry device 1110 such asa guide wire or flexible stylet with a tissue penetrating tip may beadvanced through the lumen 1104 of the shaft 1102 to exit the re-entryport 1106 as shown in FIG. 11B. This arrangement may be used toestablish re-entry of the native lumen of a vessel once the device 1100traverses an occlusion in the subintimal space.

With reference to FIGS. 12A-12D, an alternative re-entry method isschematically shown. In this method, a subintimal device such as guidewire 1210 is advanced into the subintimal space 1202 across an occlusion1200 in a manner similar to the methods described previously, forexample. As shown in FIG. 12A, the guide wire 1210 extends across anocclusion 1200 disposed in subintimal space 1202 between intimal/mediallayers 1204 and adventitial layer 1206, where re-entry of the nativelumen 1208 distal of the occlusion 1200 is desired. A balloon catheter1220 is then advanced over the guide wire 1210 until the balloon portionis disposed adjacent the distal end of the occlusion as shown in FIGS.12B and 12C. The guide wire 1210 is pulled proximally and balloon isthen inflated causing radial displacement of the distal end of theballoon catheter 1220 as shown in FIG. 12C. Inflating the balloon of theballoon catheter 1220 orients the tip of the catheter toward theintimal/medial layers 1204. The guide wire 1210 may be removed from theballoon catheter 1220 and a sharpened stylet 1230 or the like may beadvanced through the guide wire lumen of the catheter 1220 until thedistal end of the stylet 1230 penetrates the intimal/medial layers 1204as shown in FIG. 12D, thus establishing re-entry from the subintimalpath 1202 and into the native lumen 1208.

With reference to FIGS. 13A and 13B, an alternative fluidic subintimalsystem 1300 with subintimal device 1310 and associated pumping system1320 is shown schematically. The fluidic system 1300 is similar incertain aspects to the arrangements described with reference to FIGS. 3,4 and 5, the various aspects of which may be combined or used in thealternative as will be appreciated by those skilled in the art. System1300 includes a subintimal device 1310 which may comprise any of thetubular subintimal devices described herein. Generally, subintimaldevice 1310 includes a tubular shaft 1312 having a proximal endconnected to a pumping mechanism 1320. A plunger rod 1314 is slidinglydisposed in the tubular shaft 1312 as shown in FIG. 13B and its proximalend is connected to a linear actuator 1322 of the pumping mechanism asshown in FIG. 13A. As seen in FIG. 13B, a ring seal 1315 is disposed inthe lumen of shaft 1312 around the rod 1314. The rod 1314 extendsthrough the tubular shaft 1312 to a point proximal of the distal endthereof to define a pumping chamber 1316. A source of liquid 1330 (e.g.,saline bag) is connected to the proximal end of the subintimal device1310 via a fluid line 1332 and optional valve 1334 to supply liquid tothe annular lumen between the rod 1314 and the inner wall of the tubularshaft 1312. As the linear actuator moves the rod 1314 back and forth inthe tubular shaft 1312, liquid is caused to be expelled out of thechamber 1316 in a pulsatile fashion, which may be used to hydraulicallydissect tissues to define a subintimal path as described previously, forexample. The stroke length, stroke rate and stroke volume may beadjusted to achieve the desired effect. For example, the stroke volumeof the chamber 1316 may be relatively small (0.01 cc-1.0 cc, forexample) such that liquid exits the chamber 1316 with high energy thatdissipates quickly to minimize trauma to tissues as they are dissected.

From the foregoing, it will be apparent to those skilled in the art thatthe present invention provides, in exemplary non-limiting embodiments,devices and methods for the treatment of chronic total occlusions.Further, those skilled in the art will recognize that the presentinvention may be manifested in a variety of forms other than thespecific embodiments described and contemplated herein. Accordingly,departures in form and detail may be made without departing from thescope and spirit of the present invention as described in the appendedclaims.

What is claimed is:
 1. A method of facilitating treatment of a bloodvessel having a vascular wall defining a vascular lumen, comprising:advancing an intravascular device into the vascular wall adjacent anocclusion in the vascular lumen, wherein the intravascular devicecomprises: an elongate member defining a lumen extending distally to anopening; and a balloon located on a distal end region of the elongatemember; wherein an exterior surface of the elongate member is exposedbetween a proximal end of the balloon and a distal end of the balloon;positioning the balloon within the vascular wall distal of theocclusion; inflating the balloon within the vascular wall in opposingdirections from the elongate member to orient the opening toward thevascular lumen.
 2. The method of claim 1, wherein the intravasculardevice further includes a re-entry device movably disposed within thelumen of the elongate member.
 3. The method of claim 2, furthercomprising: advancing the re-entry device out of the opening and througha tissue layer of the vascular wall into the vascular lumen.
 4. Themethod of claim 1, wherein the distal end region of the elongate memberis oriented substantially parallel to the vascular lumen prior toinflating the balloon.
 5. The method of claim 1, wherein at least aportion of the balloon is inflated in a direction away from the vascularlumen.
 6. The method of claim 1, wherein a radially outermost edge of afirst balloon portion, relative to the elongate member, is straight. 7.The method of claim 6, wherein the straight radially outermost edge ofthe first balloon portion is parallel with a longitudinal axis of thelumen defined by the elongate member.
 8. The method of claim 6, whereina radially outermost edge of a second balloon portion, relative to theelongate member, is straight and substantially parallel to the straightradially outermost edge of the first balloon portion.
 9. A method offacilitating treatment of a blood vessel having a vascular wall havingan innermost surface defining a vascular lumen and an outermost surfacefurthest from the vascular lumen, comprising: advancing an intravasculardevice into the vascular wall adjacent an occlusion in the vascularlumen, wherein the intravascular device comprises: an elongate memberdefining a lumen extending distally to an opening; and a balloon locatedon a distal region of the elongate member, the balloon having a firstballoon portion configured to extend radially outward in a firstdirection and a second balloon portion configured to extend radiallyoutward in a second direction opposite the first direction; wherein anexterior surface of the elongate member is exposed between a proximalend of the balloon and a distal end of the balloon; positioning theballoon within the vascular wall between the innermost surface and theoutermost surface distal of the occlusion; inflating the balloon withinthe vascular wall in to orient the opening toward the vascular lumenwhile all surfaces of the balloon remain outside of the vascular lumenand radially inward of the outermost surface.
 10. The method of claim 9,wherein the intravascular device further includes a re-entry devicemovably disposed within the lumen of the elongate member.
 11. The methodof claim 10, further comprising: advancing the re-entry device out ofthe opening and through a tissue layer of the vascular wall into thevascular lumen.
 12. The method of claim 9, wherein the distal region ofthe elongate member is oriented substantially parallel to the vascularlumen prior to inflating the balloon.
 13. The method of claim 9, whereinthe distal region of the elongate member is oriented at an oblique angleto the vascular lumen after inflating the balloon.
 14. The method ofclaim 9, wherein the first and second balloon portions are configuredsuch that inflating the first and second balloon portions within thevascular wall bends the elongate member to direct the opening toward thevascular lumen.
 15. A method of facilitating treatment of a blood vesselhaving a vascular wall defining a vascular lumen, comprising: insertinga guidewire into the vascular wall from the vascular lumen; advancing anintravascular device over the guidewire into the vascular wall adjacentan occlusion in the vascular lumen, wherein the intravascular devicecomprises: an elongate member defining a lumen extending distally to adistal opening; and a balloon located on a distal end region of theelongate member proximal of the distal opening; wherein an exteriorsurface of the elongate member is exposed between a proximal end of theballoon and a distal end of the balloon; positioning the balloon withinthe vascular wall distal of the occlusion; removing the guidewire fromthe intravascular device; inflating the balloon within the vascular walldistal of the occlusion in opposing directions from the elongate memberto orient the distal opening toward the vascular lumen, wherein theexposed exterior surface of the elongate member remains exposed afterinflating the balloon.
 16. The method of claim 15, further comprising:advancing a re-entry device having a tissue penetrating tip through thelumen of the elongate member, out of the distal opening of the elongatemember, and through an innermost surface of the vascular wall into thevascular lumen.
 17. The method of claim 15, wherein the distal endregion of the elongate member is oriented substantially parallel to thevascular lumen prior to inflating the balloon.
 18. The method of claim17, wherein the distal end region of the elongate member is oriented atan oblique angle to the vascular lumen after inflating the balloon. 19.The method of claim 15, wherein inflating the balloon within thevascular wall bends the elongate member to direct the distal openingtoward the vascular lumen.
 20. The method of claim 15, wherein at leasta portion of the balloon is inflated in a direction toward the vascularlumen.